Materials List: film canisters; various materials for weighing such as salt, powdered sugar, dirt, cotton balls, marbles, water, etc; Unifix™ cubes; pan balances; measuring cups; various containers brought from home for measuring volume; multi-purpose buckets to hold water
Teacher Note: Students will complete two investigation tasks to determine weight/mass and volume.
Background Information: All matter takes up space and has mass. All objects have gravity pulling them towards the center of Earth. Weight is the measure of that force on an object. Mass is the actual quantity of matter or material in that object. Because weight is the measurement of gravitational force on an object, the farther one is away from the center of Earth the less one weighs. The amount of space the matter takes up is referred to as its volume.
Investigation Task 1: Students will work in small groups to determine the weight/mass of objects. Each group of students will use film canisters filled with varying materials, such as salt, sugar, powdered sugar, sand, rice, flour, dirt, cotton balls, water, and oil. Be certain to label each canister (a, b, c, etc.) for easy identification and to fill each set of canisters with the same amount of materials. For example, all salt canisters should have the same amount of salt, same with sugar and so on.
The students will predict the order of the canisters from lightest to heaviest by handling the canisters and recording the canister numbers in their journals. Next, the students will use a pan balance and counting items such as Unifix™ cubes to weigh each canister. Using a “T” chart labeled “canister letter” and “number of cubes,” the students will record data about each canister. Next the students will record the actual order of the canisters from lightest to heaviest and compare this data to their predicted outcome. As students work, the teacher should circulate around to the groups to address confusions and/or ask probing questions to assess student understanding informally.
Investigation Task 2: In this activity the students will explore measuring liquids. Review safety rules for dealing with spills. Liquids do not have a definite shape but do take up a definite amount of space or volume. In order to measure liquids, they must be poured into containers. Have students bring in containers from home to use for this activity to make real world connections. Provide the students with various containers and a plastic pan filled with water. Before filling the containers with water, have students predict which container will hold the most or least water. Have students use measuring cups to determine the volume of the containers and record the amounts in their science learning logs. Often times the shape of the container affects how we think about the container volume.
· Did your findings confirm your predictions? Why or why not?
· How and why do weight/mass and volume (capacity) differ?